Physical Review Research (Sep 2024)

Measurements of extended magnetic fields in laser-solid interaction

  • J. Griff-McMahon,
  • S. Malko,
  • V. Valenzuela-Villaseca,
  • C. A. Walsh,
  • G. Fiksel,
  • M. J. Rosenberg,
  • D. B. Schaeffer,
  • W. Fox

DOI
https://doi.org/10.1103/PhysRevResearch.6.033312
Journal volume & issue
Vol. 6, no. 3
p. 033312

Abstract

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Magnetic fields generated from a laser-foil interaction are measured with high fidelity using a proton radiography scheme with in situ x-ray fiducials. In contrast to prior findings under similar experimental conditions, this technique reveals the self-generated, Biermann-battery fields extend beyond the edge of the expanding plasma plume to a radius of over 3.5 mm by t=+1.4 ns. An analysis of two monoenergetic proton populations confirms that proton deflection is dominated by magnetic fields far from the interaction (>2 mm) and electric fields are insignificant. The results are not captured in state-of-the-art magnetohydrodynamics simulations and suggest the need to consider additional physics mechanisms for the magnetic field generation and transport in laser-solid interactions.